Wherever in home or public places like hotels or restaurants, hot water are often available by water supply pipe and the water temperature can be adjusted. Ordinarily, people use their own hands to determine whether the water temperature is suitable or not, if it is not, they have to adjust the temperature until it is suitable to use. There have inconveniences in the above mentioned method: firstly, it is uncomfortable to adjusting the temperature by hands whether the water is too hot or too cold; secondly, it would waste water in such adjusting process; thirdly, the water temperature can not be precisely adjusted, it may not keep the same water temperature in the next time.
Chinese Patent Number CN200520072341.6 titled “Tap with Temp Data Display”, it can sense water temperature by using the temperature sensor, then display the water temperature by digital thermometer. Chinese Patent Number CN200720108996.3, titled “Water Tap Displaying Temperature” has the much the same structure. Chinese Patent Number CN200520056948.5 titled “Temp Displaying Water Tap”, which discloses a temperature sensor wherein the predetermined color on the outer surface of the outflow pipe will be changed according to the change of temperature. There are many similar techniques.